Subtitles of the Movie

Now that left us 3 bits left over which we can mix and match to define the host for each subnet. Well but see how many possible combinations there are for 3 bits, let's just lay them all out here. Triple 0 the decimal equivalent is 0, 0011010 gives us 2 and so on to 7. So in other words we have combinations 0 through 7 or we have 2 to the 3rd possible hosts. What does that equal? It equals 8 but remember there were two combinations we can't use. We can't use that combination and we can't use that combination. Why? All zeros, all ones in the host identifier. So using these rules we will have defined several new subnets out of this one given network ID. The first custom network is going to be 192.168.2.0 it's going to match this one with a subnet mask of 255.255.248, here's where it gets interesting, the second one is going to be 192.168.2.8. How do I know that's going to define the second subnet? Because if I look at my network number here and look at it the way the computer looks at it, remember these first 29 bits are going to be masked out. So the first new combination of these 5 ones and zeros will be a 1, turning that on. So if I turn that on and leave the rest off, I have 192.168.2.8. The first client on that second subnet they're going to get an IP address of 192.168.2.9, which in binary looks like that. So that's going to be the IP address, the subnet mask is going to look like that, 255.255.255.248 and so on, the third subnet that we're going to be able to define here, is going to be 192.168.2. turn this off, turn this on and that's the network identifier, what's the equivalent for this octet? It is going to be 16. So that's the 3rd network the first client is going to be set. So if we see a computer with an IP address like this with a subnet mask like this, we can say that this client is the first client on the 16 network. Notice when we define subnet mask, custom subnet mask that becomes harder to see right away the network that it lives on. We have to look at IP addresses the same way that computers look at IP addresses. Which is why we spent so much time learning and getting familiar with binary notation.